Say "yes" instead

"The leaves stay on the plant. I see you want to play with the plant. Come, let's water it toghether". Or simply "The leaves stay on the plant" instead of "Don't remove the leaves". If he doesn't stop, phisically move him and re-direct.

Until they are 3 more or less they can't understand that they are not meant to do something because is "wrong". And often they act on impulses that they can't understand. Calmly, confidently, respectfully set a limit and then re-direct.

"You want to throw. Blocks are for building. I get you your balls. You can throw your balls."

Short, simple sentences. And let's be prepared to repeat them. Infinitely many times.

"(I don't want that you run inside). Running is for outside" rather than "Don't run".

"Just for looking / hands behind your back" instead of "Don't touch". 

Feedom within limits. We say "yes" to the behavior but "no" to the contest.

"The plate stays on the table" rather than "don't throw the plate" 

or also 

"I see you are finished. Give me your plate, please".

 Let them experience consequences (consequences. Not punishments).

"If you throw the plate again, I understand you are finished and I will take it away".

I try to ask myself
1) Is the no really needed?
2) Often, a particular behaviour is a consequence of an internal need. How can I meet that emotional need? When and where is this an accepted behaviour?

"We don't hit. I won't let you hit." and more "I see you are angry. Here, you can hit this pillow instead".
"I see you want to spit. Come, let's spit water in the basin"
(Very useful skill for tooth-brushing!).

I also try to avoid flat out "NO".

When possible, I replace the no with STOP or ALT, followed by a brief explanation.
Or I set them limit in first-person.
"I won't let you touch the oven. It's hot. It's dangerous". Firm, but calm, and kind. And repeated. If he keeps going, physically remove him.

There is nothing wrong with "no", but I've decided to save it for the real dangers. And to do it consistently.

I also try to remember that no matter how few the no's are, toddlers will challenge them, test them, to test the limits of the world, to test we can be confident, strong leaders. 
It's a vital need for them, they are not challenging us personally, definitely not manipulating us.
Let's offer them those limits they crave for.
And let's accept that they can, and will, protest.
Lorenzo has the right to strong reaction. Especially when he's not verbal yet and can't explain himself.
I will try to:
- be calm, be confident, be the adult.
- be present. Acknowledge his feeling. Give him the words he's missing ("You wanted to rip apart the leaves. I didn't let you. You are frustrated").
- Contain him. Physically, if he lets me. Being besides him otherwise. Welcome him throughout his reaction, make him feel he's still loved, no matter what.
- Recognize my right to strong feeling. "I need a minute to calm down. I'm in the bedroom if you need me".

Long post. In summary:
- Riformulate the forbidding in a positive way.
Rather than tell him what he can't do, tell him what he CAN do instead.
- It's a basic concept in communication. A marketing student would sell this post way better than me.
"Don't walk on the street"
Which image is planting in our head? In mine, a street.
What about "Walk on the footpath"?

Reading:

Janet Lansbury RIE blog / books
How to talk so kids will listen and listen so kids will talk
The Whole-Brain Child: 12 Revolutionary Strategies to Nurture Your Child's Developing Mind